1. Field of the Invention
This invention generally relates to a bicycle hub. More specifically, the invention relates to an internal motorized bicycle hub in which a hub axle and an inner race of a bearing supporting a rotor do not easily become worn.
2. Background Information
An assisted bicycle is known in which a drive force imparted by human power is supplemented with a motor. In some cases, an assisted bicycle is provided with a bicycle hub that is equipped an internal motor. Typically, a conventional internal motorized bicycle hill) has a rotor that is supported by a left-right pair of roller bearings (e.g., see Japanese Laid-Open Patent Publication No. 2005-335536). The conventional bicycle hub also has an inner rotor structure that is rotatably supported on a hub axle with a left-right pair of roller bearings. Normally, the roller bearings are installed such that one of the inner race and the outer race is attached with an interference or friction fit and the other race is attached with a clearance fit. A conventional bearing is installed from one side of the rotor. Typically, a conventional roller bearing is installed such that the inner race is attached with a clearance fit and the outer race is attached with an interference fit, because the inner race is not restricted while the external diameter of the outer race is varied and restricted.